To any self-respecting hacker, Ted Nelson needs no introduction. Philosopher, showman, genius, and gadfly: Nelson is Professional Visionary. He sees the future of computing. And he has been remarkably successful--­at seeing things. He forecast word processing, he forecast hypertext. And in 1967, he forecast the Web. One day a big, networked structure of information will connect computers, he wrote. And "it will be read from an illuminated screen; the cathode-ray display; it will respond or branch upon actions by the user." Needless to say, the Web has happened: You could put money on his visions. Well, almost. His business ventures have yet to meet with success. Especially his greatest vision, the vision of a global writing system: Xanadu. A lifetime's obsession wrapped into one massive program. A program that has been in development for over 40 years, causing Wired magazine to label it "the longest-running vaporware project in the history of computing." Much to Nelson's dismay. But despite years of criticism from the digerati, Xanadu refuses to die. It has become an image of potentiality within the hypertext community. And like a specter of the future, all we have of Xanadu is its erotic simulacrum, its ideal, its idea. A computer filing system which would store and deliver the great body of human thought, in all its historical versions and with all its messy interconnections, acknowledging authorship and ownership. A nonlinear writing system. Like the Web, but much better.